Expo Publish Error - Validating asset fields in app.json

Hello everyone! I am not a dev, but I am trying to download the code on Expo Go and I run into this issue.
littlewhitepaw@Littlewhites-MacBook-Pro code % expo publish

› Expo SDK: 38.0.0
› Release channel: default
› Workflow: Managed

Building optimized bundles and generating sourcemaps…
Error: Problem validating asset fields in app.json. Learn more: https://docs.expo.dev/
• Field: icon - image should be square, but the file at ‘./assets/GullyIcon.png’ has dimensions 710x709.
• Field: notification.icon - image should be square, but the file at ‘./assets/GullyIcon.png’ has dimensions 710x709.
Couldn’t publish because errors were found. (See logs above.) Please fix the errors and try again.

What should I do? I tried to install the -g sharp-cli and expo-optimize but still didn’t work.
Please guide me a little.

Thanks!